If the Mini is only going to be updated once every three years, and only have very-low-end configurations, and be utterly unexpandable -- I just don't see the Mini as a going concern any more.
Perhaps my needs don't fit into Apple's current Mac lineup. I'm a cheapskate; I'll never be able to afford the Pro, and the iMac integrates features I don't want and then forces me to pay for them. For a long time now, the Mini fit the bill for me -- access to the wonderful OS X, decent power, acceptable price. But if I'm going to use that machine as my main computing device, I need an upgrade path. I need some assurance that, at some point in the not-so-distant future, I'm going to be able to replace my current machine with a new one, should something happen to it.
Apple is not providing any such assurances. Sure, they may update the Mini in the future. But they are giving no hints as to what features that machine may have, nor even any confirmation that there will be a future Mini.
This is not a game! My computer is not a toy; it is a tool I use every day to get work done. If I can't depend upon that tool being there for me in the future and doing the job I need it to do, the I need to be looking for a different tool...